Common diseases of guinea pigs (Proceedings)

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Guinea pigs need Vitamin C supplementation as they lack L-gulonolactone oxidase which is involved in synthesis of ascorbic acid from glucose therefore they are unable to manufacture or store vitamin C.

Heat stroke common

     • Signs: listlessness, raising of head, shallow rapid breathing

     • Tx: cool immediately by wrapping in a towel soaked in cool water or spray with cool water. +/- cool pedialyte® offered orally; SQ, IO, IP or IV fluids may also be necessary

Respiratory Infections

     • Very susceptible to upper resp. infections

     • Symptoms: nasal discharge, sneezing, difficulty breathing

     • Bordetella bronchiseptica & Strep. Pneumoniae are the most common

     • Can quickly lead to pneumonia

          o SMZ-TMP at 15-30mg/kg PO BID

          o Enrofloxicin at 5-10mg/kg PO BID

          o Doxycycline 2.5-5mg/kg PO BID

Conjunctivitis

     • Most common in neonates

     • Chlamydia most common pathogen

     • Treat with topical tetracycline (Terramycin®) - Systemic treatment usually not necessary

Normal/Behavioral Dermatologic Conditions

Normal alopecia behind ear and on medial aspect of front inner legs Sebaceous glands are abundant along the dorsal surface of the guinea pig and around the anal opening. These sebaceous glands are testosterone dependent and the sebaceous secretions can be excessive in the adult male. May see clumping of hair and can lead to dermatitis in this region.

Alopecia in females can be caused by a Telogen deflexion freq. seen last trimester of pregnancy or during lactation. The alopecia is most prominent on lumbosacral area and flanks. Thinning of haircoat is also common at weaning and spontaneously resolves.

     • Barbering

     • Behavioral

          o Self-induced or by cagemates

     • Treatmen

          o Isolate pig, apply Bitter apple spray, Ignore, Increase hay (fiber)

          o Check for a Nutritional deficiency

Vitamin C Deficiency

Guinea pigs need Vitamin C supplementation as they lack L-gulonolactone oxidase which is involved in synthesis of ascorbic acid from glucose therefore they are unable to manufacture or store vitamin C. Clinical signs include: Cutaneous petechiae, Echymoses, Hematomas, Gingival & Periarticular joint hemorrhages (lameness), Anorexia/dehydration, Generalized scaling, Rough & unkept haircoat, Secondary bacterial infections. Clinical signs usually develop within 10-14 days Juveniles appear to be more susceptible to Vitamin C deficiency Prevention consists of using commercially available Guinea pig pellets that has a milled date not to exceed 90 days and stored in an airtight container away from heat and sunlight. Vegetables high in vitamin C should also be offered. Any sick guinea pig should always be supplemented with vitamin C at 30mg/kg/day or 200-400mg/L drinking water. Oversupplementation has been reported to lead to urinary stone formation and osteoarthritis.

Ovarian cysts

     • 76% of female guinea pigs btw 2-4 years will develop this spontaneously

     • Clinical signs: Bilateral symmetrical alopecia over the flank & trunk

     • Treatment = OVH

Pregnancy Toxemia/Dystocia

Female guinea pigs have a high perinatal mortality rate. Still births and dystocias are related to large fetuses, subclinical ketosis, and fusion of the pubic symphysis due to ossification that occurs after 6 months of age. Pregnancy toxemia can often develop during late pregnancy in guinea pigs. There are 2 recognized forms of pregnancy toxemia: fasting/metabolic and circulatory/toxic. Clinical signs for both consist of depression, acidosis, ketosis, proteinuria, ketonuria, and a more acid urine pH of 5 or 6 vs the normal 9. Aggressive treatment is necessary but is rarely successful in advanced cases. Treatment of metabolic toxemia consists of 5% glucose solution IV or SQ, nutritional supplementation, and C-section. Circulatory form is due to the large uterus compressing the aorta resulting in dec. blood flow to uterus leading to placental necrosis. Therefore treatment of this is emergency c-section.

Trichofolliculoma

     • Most common benign skin tumor

     • Usually located in dorsal lumbar region

     • Usually central pore where keratinous material is discharged

     • Cystic, non-encapsulated

     • Extension from epidermis to subcutis

     • Treatment: surgical removal

Trichophyton mentagrophytes

     • Can be isolated in up to 15 % of normal guinea pigs

     • Clinical signs: Scaling, broken hairs and alopecia on nose which spreads to periocular, forehead, and pinnal areas. It is Zoonotic.

     • Treatment consists of daily topical antifungal agents such as chlortrimazole or miconazole or baths/dips with 2% lime sulfur, 4% chlorhexidine, 0.2% Enilconazol that should occur weekly until animal is cured. Griseofulvin usually not needed but dose would be 25mg/kg PO q 24hrs

Lice

     • Gliricola porcelli (more common)

     • Gyropus ovalis

     • Common – occur without clinical signs

     • Heavy infestations may cause scaling, rough haircoat, crusting, alopecia

     • Treatment consists of Pyrethrin shampoos safe for kittens. Advantage, Ivermectin, 2% lime sulfur dip, and Revolution have also been used. The most important part of treatment is to clean up the environment!

Mite - Trixacarus caviae

     • #1 DDX for intense pruritus; Hairloss, self-trauma, flaking most common along dorsal neck and thorax.

     • Can temporarily infest human and cause a pruritic, papular dermatitis

     • Treatment:

          o Ivermectin 800-1000 mcg/kg SQ

          o Repeat in 21 days

          o 2% lime sulfur dips once weekly until cure

          o Revolution® at 10-20mg/pound applied topically

          o Repeat in 21 days

Pododermatitis

     • Staphlococcus sp. (aureus)

     • Trauma induce

          o Guinea pigs very clumsy

          o Foreign material in cage (ex. Cloth, string)

          o Vitamin C deficiency

          o Rough surface to cage

          o Poor hygiene/sanitation

          o Long toenails

          o Obesity

          o Aging

Treatment involves correcting husbandry; foot soaks with Chlorhexidine or providone iodine and topical antibiotics. Depending on the severity systemic antibiotics such as SMZ/TMP or Enrofloxacin may be warranted.

Cervical Lymphadenitis

     • Streptococcus zooepidemicus #1

     • Streptobacillus monifiliformis

     • Pasturella

     • Fusobacterium

     • Strep. Zooepidemicus normally present in conjunctive & nasal cavity and infection occurs when oral mucosa becomes abraded by malocclusion, dietary roughage, or biting and the bacteria enters the blood stream and travels to cervical LN. Treatment consists of culture and sensitivity, lance to drain or surgical removal. Systemic antibiotics – SMZ/TMP or Enrofloxacin are warranted. Prevention consists of keeping the environment clean, stress-free & provide a good diet.

Diarrhea/Enteritis

     • Many causes with the most common being: Overfeeding of greens, Bacterial infection, Antibiotic associated Enterotoxemia (Gram + gut flora destroyed leading to Clostridium toxin production), Parasitic, etc.

     • Enteritis due to Salmonella typhimurium or enteritis

     • Clinical signs: weight loss, weakness, conjunctivitis, abortion,

     • Treatment controversial due to carriers/zoonosis and possibility of antibiotic resistant salmonella. Must keep guinea pig well hydrated either with IO, IV or SQ fluids. Antibiotics may be needed to treat toxemia. Provide large amounts of fresh hay to inc. fiber in diet to achieve gut normality. If diarrhea semi-formed and in normal amounts then one can try withholding greens, feeding a large amounts of fresh hay, and increasing fluid intake .

Broken tooth/teeth

     • Occurs from chewing on hard objects or from a fall

     • Usually the tooth will grow back in 2-3 weeks

     • Trimming of sharp edges may be needed

     • Trimming of opposite tooth may be needed to prevent overgrowth

     • Oral antibiotics may be necessary if infection occurs or if broken with pulp cavity exposure

Malocclusion and Impacted Molars

Cheek teeth malocclusion with overgrowth of the cheek teeth is especially common in guinea pigs raised exclusively on a pellet diet only and no hay. Frequent oral exams under general anesthesia are necessary and trimming of these crown are needed with a dental burr. Eventually the crowns of the teeth stop progressing into the mouth, but the roots continue to grow. As the roots grow into the bone a painful inflammation of the bone occurs which will often cause the Guinea Pig to stop eating. At this time there is no cure for this disease, although medications can decrease the Guinea Pig's pain and inflammation

Urolithiasis

     • Frequently seen in middle aged and older pigs >2.5 years with females being over represented. Stones are usually composed of calcium salts (phosphate or oxalate#1) so unable to dissolve stones with diet or urine pH modifiers. Stones can be found anywhere in urinary tract (bladder, kidneys, urethra or ureters)

     • Clinical signs based on location and size of the stone

          o Lower = hematuria, stranguria, dysuria

          o Ureter = very painful (inappetance, dec. activity)

     • Diagnosis with radiographs

          o Make sure to do 2 views (If bladder stone off midline then most likely have a stone in distal ureter)

     • Treatment Surgery

          o Medical management unrewarding

          o Antibiotics, pain meds, diet modification

     • Diet modification

          o Reduce intake of calcium

          o Alfalfa

          o Reduce intake of oxalates

          o Spinach, parsley, celery, strawberries, and Vitamin C

Hyperthyroidism/Thyroid Neoplasia

Most reported cases occur in animals over 3 years of age. Thyroid hyperplasia, adenoma, and carcinoma all have been responsible for clinical signs. Clinical signs varied significantly. These include hyperactivity and hyperesthesia; animals often are polyphagic but appear thin or to be losing weight, diarrhea or soft stool, polyuria/polydipsia, and a palpable mass in the neck.

The diagnosis can be difficult as results from various diagnostic tests can often be inconclusive. The T4 and T3 blood concentrations have been unreliable indicators. A fine needle aspirate with cytological evaluation can aid in the diagnosis of a thyroid tumor. There are several treatment options with pros and cons for each: Medical, surgical, percutaneous ethanol injection, or Radioactive treatment with I-131. The drug of choice for medical management is methimazole, which has been used in cats with the same problem. Drug dosages have been extrapolated from cat dosages and range from 0.5 to 2 mg/kg PO q24h.

Suggested Reading

1. Donnelly T, Brown C: Guinea Pig and chinchilla care and husbandry In Vet Clinics of North American Exotic Animal Practice, Saunders, May 2004, 7:2, p351-372

2. Johnson-Delaney C: What veterinarians need to know about Guinea Pigs In Exotic DVM, volume 10 issue 3, p36-43.

3. Quesenberry K, Donnelly T, Hillyer E: Guinea pigs In Quesenberry KE, Carpenter JW (eds): Ferrets, Rabbits, and Rodents Clinical medicine and surgery 2nd ed. WB Saunders, 2004, p232-238.

4. American Cavy Breeders Association (ACBA) www.acbaonline.com

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